1. Field of the Invention
The present invention relates to a magnetic head supporting mechanism for supporting a magnetic head of a flexible magnetic disk memory device and, more particularly, to a gimbal structure of such a magnetic head supporting mechanism which supports the magnetic head on a carriage of the flexible magnetic disk memory device.
2. Description of the Background Art
In a conventional flexible magnetic disk memory device, one of a pair of magnetic heads is fixed and the other of the pair movably supported. This latter is elastically supported in a direction normal to a surface of a magnetic disk (up and down), a direction of rotation around an axis tangent to the disk (around a rolling axis), and a direction of rotation around an axis along the radius of the disk (around a pitching axis), as in that the described in U.S. Pat. No. 4,151,573.
Such a configuration has an advantage that the alignment of the fixed magnetic head becomes easier, but also has a disadvantage that the durability of the magnetic disk is impaired as the magnetic disk is forced to distort along with the magnetic head. If the elasticity of the magnetic disk is increased, proper head contact may not be achieved, so that the magnetic head floats over the magnetic disk. In addition, it is necessary to have an accurate positional relationship between the magnetic head and the magnetic disk.
On the other hand, there is a configuration in which both of the pair of magnetic heads are movably elastically supported in the up and down direction, the direction of rotation around the rolling axis, and the direction of the rotation around the pitching axis, as described in U.S. Pat. No. 4,306,258.
In this case, the elasticity in these three directions are obtained by means of a gimbal, whose deformation gives rise to head pressing load. However, it is impossible to have ample elasticity in all of the three directions in this configuration, as there is only one gimbal. Also, when the elasticity in two of the three directions is made large, it is necessary to have two magnetic heads of the pair accurately parallel in order to obtain a good contact between the magnetic heads and the magnetic disk, and if the magnetic heads are tilted due to some assembly error the head pressing load needs to be increased. But the increased head pressing load causes deformation on the gimbal, and the resulting non-linearity makes the elasticity in the up and down direction too large, so that it becomes almost like a fixed head configuration. This results in reduction of productivity and durability of the magnetic disk. Furthermore, vibrations of the magnetic heads due to their flaccidity makes the head contact unstable.
To cope with this situation, there are proposed solutions, such as those in Japanese Patent Laying Open No. S56-105358 and No. S62-22267, in which the nonlinearity is reduced by providing double gimbels; and that in Japanese Patent Laying Open No. S61-231762, by the present applicant, in which the spring constant around the rolling axis is made larger than that around the pitching axis, but further improvement is still required.
Thus, the conventional configuration is unable to provide a satisfactory state of contact between the magnetic heads and the magnetic disk, because of the insufficient consideration on the elastic supporting structure of the gimbal.